Our major research goal is to understand the mechanisms responsible for the development of hypertriglyceridemia, and we plan two approaches in this regard. One series of experiments will be aimed at establishing the existence of insulin resistance in non-obese subjects with hypertriglyceridemia. If, as we expect, this abnormality exists in these subjects, we will attempt to define the locus of the insulin resistance and the possible role that circulating insulin antagonists and/or abnormal insulin binding might play in this phenomenon. In a second series of investigations we plan a combined ultrastructural and functional study of the role of intestinal lipoprotein metabolism under normal conditions and in situations characterized by either increases or decreases in VLDL production.